Drawing aid

ABSTRACT

A drawing aid for assisting in the marking of lines or other markings on sheet material incorporates a blade-like portion (2) which is connected with a location region (1A, 2A) which includes means (4, 5) deformable relative to the blade-like portion to be able to provide abutment surfaces which enable the aid to so co-operate with the actual edge of a sheet (8) of flexible or non-rigid material such as a sheet of paper as to use the edge (11) as the guide for the aid during the positional adjustment thereof to the location at which it is desired to draw lines or the like on the sheet (8). When the aid is engaged with a sheet edge (11) a part (1A, 2A) of the aid (1) presses on the sheet marginal edge (11A) to remove any buckles etc. and also to prevent any relative displacement of aid and sheet.

This invention relate to drawing aids.

In particular, the present invention is concerned with an arrangementfor facilitating the drawing, marking or scribing of continous lines,series of dots or dashes or combinations thereof on a sheet of markablematerial in such manner that the lines etc., are aligned at apredetermined orientation with respect to a reference direction, such asthe edge of the sheet.

In this specification the term markable material is intended to includepaper, card, plastics, metal sheet or foil in extended area form andwhich is of such thickness or characteristic as to be flexible ornonrigid.

It is known to provide aids for drawing lines or series of dots, dashesetc., at a predetermined angle with respect to a reference direction.

One such aid, commonly called a Tee Square, includes a wooden or otherrigid material elongate stock defining a reference face or edge alongthe length thereof and an elongate blade of which at least one of thelonger edges thereof is intended to provide a straight edge or guideface for a writing or marking implement, this straight edge or guideface being conventionally perpendicular to the stock reference face oredge.

In use of the known Tee Square it is necessary for the stock referenceedge to abut the side or end face of a raised platform such as a drawingboard or drafting table upon which the sheet material to be marked hasbeen previously secured in place.

In practice, the sheet of material is conventionally `set` or orientedfor the purposes of drawing thereupon by engaging the Tee Square stockwith one of the end faces of the board or table and then causing thelower edge of the sheet of paper to abut the Tee Square blade guide edgethereby to ensure that the lower edge of the paper sheet is parallel tothe Tee Square blade guide edge. Following this alignment, the paper isfirmly secured i.e., pinned or taped to the board or table so as toprevent any subsequent movement. In using the Tee Square the latter ismoved up or down whilst maintaining the stock against the board or tablewith respect to the paper sheet and lines etc., are drawn whererequired.

Since the Tee Square stock needs to have considerable depth or thicknessfor the purposes of structural strength and rigidity it is, in practice,necessary positively to secure the sheet material on a platform (i.e.,board or table) which provides an accurately rectilinear reference edgeof an adequate vertical depth for the effective use of the Tee Square.If this platform is not available it is not possible to use the TeeSquare. Consequently, the use of a Tee Square or like drawing aid iswholly restricted to the availability of the support platform with therequisite accuracy in construction for receiving and guiding the The TeeSquare stock edge. In other words the known Tee Square constructionscannot be regarded as being suitable as a portable drawing aid.

It is an object of the present invention to provide a drawing aid whichavoids the above mentioned difficulties such as the need for a platformtype of sheet support with an accurate guide edge.

According to the present invention there is provided a drawing aidincorporating at least one guide edge for co-operation with a materialmarking means, for facilitating the drawing of lines or other markingsupon sheet material lying upon a support surface, characterised in thatthe drawing aid is adapted to utilise a marginal edge region of a sheetof material in such manner that the sheet edge is caused to provide areference or direction guide for the drawing aid when operationallysetting or positioning the aid with respect to the sheet.

Conveniently the adaptation is such that when the aid is in co-operationwith the marginal edge region relative movement between the sheet andthe aid and between the sheet and the support surface is simultaneouslyprevented.

In a preferred construction the aid incorporates an elongate bladeportion defining said at least one guide edge and in addition the aidincludes a location portion adapted for co-operation with an edge of thesheet to set the guide edge at a predetermined direction with respect tothe edge of the sheet.

For a better understanding of the invention and to show how to carry thesame into effect reference will now be made to the accompanying drawingsin which:

FIG. 1 is a diagrammatic plan view of a first embodiment of a drawingaid for facilitating the production of lines or the like runningperpendicular to an edge of a sheet of material, i.e., a sheet of paper;

FIG. 2 is a diagrammatic side view to a larger scale of a part of thedrawing aid of FIG. 1;

FIG. 3 is a section taken upon the line III--III of FIG. 1, the sectionbeing to a larger scale than that of FIG. 1;

FIG. 4 is a schematic view in three dimensional form of a detail of thedrawing aid of FIGS. 1, 2 and 3, the FIG. 4 illustrating the drawing aidwhen operationally positioned with respect to a sheet of paper of whichonly a fragment is shown and to a larger scale than that of FIGS. 1 to3;

FIG. 5 is a diagrammatic plan view of a part of a second embodiment of adrawing aid in which the angle at which lines may be drawn isselectively variable;

FIG. 6 is a diagrammatic cross section of the drawing aid of FIG. 5;

FIG. 7 is a diagrammatic three dimensional view of a part of a furtherembodiment of a drawing aid

FIG. 8 is a fragmentary sectional view on the line IX--IX of a furtherembodiment of a drawing aid shown in FIG. 9; and

FIG. 9 is a fragmentary plan view of the further embodiment of thedrawing aid.

Referring now to FIGS. 1, 2, 3 and 4 the drawing aid 1 shown thereinincludes a main body 2 of an elongate blade like rectangular shapehaving at one end thereof lugs, arms, ears or other elements 4 and 5which extend in opposite directions from the main body and generally ina direction transverse to the length of the main body 2.

The longitudinal edges 6 and 7 of the main body 2 are parallel to eachother, with each edge being intended to provide a guide edge for amarking implement, such as a pencil, pen, scriber or the like (notshown) which is to be used to produce the requisite markings, i.e.,continuous lines, on a sheet of paper 8 (shown in FIG. 4) In addition,the edges 9 and 10 of the elements 4 and 5 are precisely in line witheach other, and, in practice, effectively combine or co-operate todefine a reference direction indicated by the dashed line R. This line Ris accurately perpendicular to the direction of the guide edges 6 and 7.

To use the drawing aid as so far described a sheet 8 of paper having astraight edge 11 is placed upon a suitable support surface 8A of whichonly a fragmentary portion is shown. The surface 8A can be a table top,book, brief case of the flat type. As will be explained hereinafter itis merely necessary to provide a flat surface for supporting the sheet 8and, furthermore, it is not necessary for the sheet to be secured to thesupport surface.

The aid is positioned upon the sheet 8 so that the element edges 9 and10 are adjacent to and are able co-operate with the edge 11 of the sheet8. Since the pencil or the like marking implement guide edges 6 and 7are perpendicular to the direction R it follows that the edges will beperpendicular to the edge 11 when the edges 9 and 10 abut the edge 11 ofthe sheet 8.

By displacing the drawing aid lengthwise of the sheet edge 11 whilstensuring the contact with the sheet edge it will be possible to drawlines or to form series of dots or dashes perpendicular to the sheetedge at any desired position lengthwise of the sheet edge 11.

Returning now to the further consideration of the Figures of thedrawings a secondary extension, plate arm, ear or element 12 projectsfrom the element 4 in the lengthwise direction of the main body. Asimilar secondary element 13 projects from the element 5. The element 12includes a horizontally directed part 12A and an inclined part 12B, thelatter extending at 45° to the part 12A. The element 13 has similarparts 13A and 13B.

User finger location means 14 are provided on the elements 4 and 5.These location means can comprise recesses; knurled or other roughenedregions or raised parts. In the FIGS. 2 and 4 raised parts in the formof rims 15 have been shown. If desired, a third finger locating meanscan be provided at the neck region 2A of the main body 2. This thirdlocation means is shown in dashed lines at 14A in FIG. 1.

The thickness of the horizontal parts 12A and 13A of the elements 12 and13 relative to the thickness of the elements 4 and 5 and also the mainbody 2 is such that the lower surfaces of the parts 12A and 13A are eachlocated above the plane of the lower surface 16 of the main body 2 andthe elements 4 and 5. With this arrangement a step or gap is produced ofsuch height dimension relative to the plane of the lower surface 16 thatthe gap or step is able to accommodate with clearance the maximumthickness of sheet material that can satisfactorily be used with thedrawing aid.

As will be seen from FIG. 4 the formation of the element 13 produces thegap or step and in so doing produces a vertical surface 13C which iseffectively an extension of the face or edge 10 of the associatedelement 5. A similar vertical surface 12C is produced by the formationof the element 12, the surface 12C forming effectively an extension ofthe face or edge 9. In other words the various surfaces and faces 9,10,12C and 13C all co-operate to provide the reference direction R.

A centrally disposed cantilever arm 17 is provided at the end of thedrawing aid that is adjacent to the elements 4 and 5. The arm 17facilitates the general lifting of the aid, by facilitating the tiltingof the main body 2 away from the sheet 8.

Two series of ribs 18 directed longitudinally of the main body projectfrom the lower surface 16 of the main body. The ribs 18 of the twoseries are parallel to each other. The ribs have a triangular crosssection so that they present a relatively sharp contact region with thesheet.

The major part of the main body 2 is stiffened in the longitudinaldirection thereof by means of an inverted channel 19 which terminatesshort of the line R defined by the surfaces and edges 9,10,12C and 13C,whereby a region is established in which a higher flexibility ispossible at the so-called neck region 2A of the main body 2. Thisenables the stiffened part of the main body slightly to flex up or downrelative to the remainder of the drawing aid 1 in the vicinity of theelements 4 and 5.

A graduated scale is provided along each edge 6 and 7 of the main body,the nature of the scales being as required i.e., a metric distancescale.

The general mode of use of the drawing aid 1 as so far considered willnow be examined. To recapitulate it has been mentioned that in use thesheet 8 of material to be marked is laid upon a larger area supportsurface 8A (only a fragmentary portion of the surface 8A being shown)and the drawing aid 1 of the invention is caused to co-operate with anedge 11 of the sheet 8.

In practice, the sheet 8 is oriented with respect to the support surface8A such that the edge 11 is located to the left hand side of the sheetand thus the user when the latter is right-handed. In the case of aleft-handed user the edge 11 would be located to the right hand side ofthe sheet and thus the user. Also for convenience of working the edge 11is arranged in a generally upright setting with respect to the positionof the user.

The mode of aligning or registering the drawing aid 1 with respect tothe edge 11 will now be examined in greater detail It will be presumedthat the edge 11 has been arranged for the benefit of a right-handeduser upon the support surface 8A.

The drawing aid is bodily moved by means of the cantilever arm 17 to alocation closely adjacent to the sheet and such that the elements 4 and5 are in the near vicinity of the edge 11 of the sheet 8. The user thenengages the second finger and thumb of the left hand in the upstandingrims 15 and if thought useful the fore finger in the recess 14A. Alsothe third finger can be used to provide an additional steadying effectto the overall feel of placement situation.

The user then exerts a sufficient pressure on the elements to establisha feel which is indicative that the elements 4 and 5 have been slightlydepressed. This initial depression causes the elements to present thevertical surfaces and edges 9,10,12C and 13C towards the adjacent edge11 of the sheet, and simultaneously causes the lower surfaces of theneck region 2A and the elements 12A, 13A in co-operation with thesupport surface 8A to confine the marginal region 8B of the sheet 8 andthus prevent buckling, thereby ensuring that the actual edge 11 of thesheet forms a substantially rectilinear guide for the vertical surfacesand edges 9,10,12C and 13C.

Following this the user than positionally adjusts the drawing aidtowards the edge until the above mentioned surfaces contact the edge 11.During this movement the user will use the right hand to restrain thesheet against displacement relative to the support surface 8A. Theadjustment of the drawing aid vertical surfaces into the contactposition with the edge 11 of of the sheet 8 normally involves a rockingor to and fro movement of the aid 1 relative to the edge 11. It will benoted that during the above mentioned stages of positional adjustment ofthe drawing aid to the edge 11 the parts 12B and 13B of the elementsassist in guiding the elements 12 and 13 over the edge 11 and preventthe elements from entering beneath the sheet.

Upon achieving the contact with the edge 11 the elements 4 and 5 arefurther depressed until the lower surfaces thereof abut the supportsurface 8A. It will be noted from the FIG. 4 that with the elements 4and 5 fully pressed into contact with the support surface 8A a clampingeffect is produced across the width of the main body in the vicinity ofthe root ends of the elements 4 and 5, that is to say, the neck region2A. In addition, the flexibility of the main body neck region 2A betweenthe reference line R and the adjacent end of the stiffening channel 19will accommodate any tendancy for the main body to tilt or lift awayfrom the sheet.

At this stage it will be found readily possible to move the drawing aidlengthwise of the sheet 8 using the edge 11 as a guide, by slightlyreleasing the firm pressure upon the elements 4 and 5. The clampingaction between the surface 16 and the support 8A is maintained by theresilience of the elements 4 and 5 and the neck 2A. During displacementof the drawing aid lengthwise of the edge 11 it will be found necessaryfor the user to restrain the sheet 8 against displacement relative tothe surface 8A by engaging the sheet with the right hand.

It has been found that the sheet tends to rotate about the user's righthand, due to the aid being pressed against the edge 11 with a force notaligned with the fulcrum formed by the right hand, such rotation makingdifficult precise positioning of the aid. The clamping action describedsubstantially reduces the tendancy of the sheet to rotate, so thatmoderate pressure by the user's right hand is sufficient to immobilisethe sheet B.

On reaching the required position the elements 4 and 5 are pressedfirmly into contact with the support surface 8A. It has been found thatonce the firm clamping action is effected by the pressure upon theelements 4 and 5 against the support 8A the sheet is also firmly held inplace so that it is no longer necessary for the user to engage the sheetwith the right hand whereby marking of the sheet can be effected withoutrelative displacement occuring between the drawing aid 1, the sheet 8and support 8A. In addition, the forefinger may be pressed on thelocation 14A (FIG. 1), which action tends to prevent any change in thealignment during a marking operation, by holding the surfaces and edges9,10,12 C and 13C in contact with edge 11.

The above mentioned step may be extended across the full width of theneck region In this case the depth of the step between edges 9 and 19 isless than the thickness of the material to be used with the aid as thestep is only intended to engage only with the upper regions of thematerial edge 11.

Furthermore, as a result of the height dimension of the gap or slot theparts 12A and 13A do not contact the surface of the sheet This factor inconjunction with the flexibility of the elements 4 and 5 makes itpossible for the drawing aid to be used with sheet material of differingthicknesses.

The basic constraint in this respect is that the engagement of theelements 4 and 5 with the support surface 8A must not be prevented bythe engagement of the parts 12A and 13A with the surface of the sheet 8.

It should also be noted that the flexibility of the elements 4 and 5makes it possible for the drawing aid to conform to a support surfacewhich is not accurately flat.

Since the drawing aid of the invention is intended for use with singlesheets of paper commonly available such as typing top copy paper, typingcopy paper or similar papers having thicknesses of the order of 0.0033inches (0.084 mm) such sheets will clearly be highly flexible ornon-rigid and easily distortable at the edge regions thereof whereby anyirregularity of the support suface 8A of the order of sixty micronswould, if the elements 4 and 5 were non-flexible prevent the elementsfrom co-operating with the edge 11 of a sheet at a location where anirregularity deeper than the sixty microns occured. By providing theflexible elements 4 and 5 such difficulties arising from a non-flatsupport surface 8A do not arise.

The previously mentioned series of ribs 18 serve a useful functionduring the setting or registration of the drawing aid relative to thesheet edge. As has been mentioned during the setting of the aid relativeto the edge 11, the user by means of his left hand swings the aidslightly with a to and fro movement. In the absence of the ribs 18 thismotion will involve moving the total surface area of the main body 2relative to the sheet surface which would then be in overall contactwith the main body. Because of such overall contact considerablefrictional force would need to be overcome in order to achieve therequisite swinging action. In addition, the ensuing rubbing contactcould induce electrostatic attraction between the main body lowersurface and the sheet surface thereby increasing the resistance to therequired movements. This in turn, causes the user to increase the forceexerted to achieve the required setting or registration movements andthus impedes a smooth movement for the adjustments.

The provision of the ribs 18 not only reduces the excessive resistanceto movement difficulties mentioned above but also tends to reduce anytendancy for the drawing aid to shift during use. This is thought toresult from the increased loca pressures which occur between the ribsand the surface of the sheet 11 as compared with the overall pressurespread over the whole area of the main body.

Referring now to FIGS. 5 and 6 these Figures illustrate a constructionin which a protractor assembly 21 is provided. In this construction themain body is effectively pivotally connected to a stub main body part 22having the elements 4 and 5 together with the elements 12 and 13 at oneend thereof. The stub body part mounts a screwed member 23 onto whichthe main body is connected by a pivotal connection. An operating head 24is provided for locking the main body in a desired setting. The stubmain body part 22 is provided with a protractor whose calibration issuch that the 90° mark lies on a line which is perpendicular to thereference line R defined by the edges 9 and 10 of the elements 4 and 5.

In use of the construction of FIGS. 5 and 6 the drawing aid will bepositionally set as discussed in relation to the embodiment of FIGS. 1to 4. In addition, the angle made by the main body edge 6 and 7 may beset as required.

It should be noted that in the FIG. 6 a support surface 8A is indicated.

The section of the aid 1 to the left of the line R that is the referencesurfaces and edges 9,10,12C and 13C and part of the neck region 2A canbe conveniently regarded as a location region 1A, the latter includingthe elements 4 and 5.

A further embodiment of the invention is shown in FIG. 7. In thisembodiment the flexible element arrangements have been replaced by abracket arrangement 26 which is mounted to the main body 2 of thedrawing aid 1.

The bracket assembly 26 includes a plate 27 connected to the main body 2by way of a transverse mounting block 28. The other end of this plate isdivided into three side-by-side strips 29, 30 and 31, which, inpractice, produce a resilient cantilever effect.

The inner one of the strips 30 is longer than the two outer strips 29and 31 and is connected at its free end to a transverse block 32 havingan inner vertical face 33. An inverted U-shaped bridge member 34 isconnected to the two outer strips 29 and 31. The bridge member 34bridges the main body 2 and includes two leg parts 35 which aregenerally in line with the end region of the inner end of the main bodyand which have bottom faces 36 that lie in a common plane.

In the FIG. 7 fragmentary portions of the sheet 8 and the supportsurface 8A are shown so that the relationship of the aid 1, when in use,to the sheet edge 11 and the surface may be seen.

In use the aid is placed in co-operation with the sheet so that the bodycan lie on the sheet with the block 34 located above the marginal edgeregion 11A of the sheet and with the inner vertical face 33 of the blockadjacent to the sheet edge 11.

The block 32 is depressed towards the surface 8A until a satisfactoryfeel is obtained between the vertical face 33 and the sheet edge 11. Inview of the structure of the bracket arrangement 26 the downwardmovement of the block 32 will automatically pull the bridge member 34downwards into contact with the marginal region 11A of the sheet 8.

The aid is the positionally adjusted as above described with respect tothe sheet to obtain the desired positional setting. Once this setting isobtained the block is pressed firmly into contact with the supportsurface 8A. This operation will automatically pull the bridge member 34into a firmer contact with the sheet marginal edge 11A.

If desired the user can exert additional pressure upon the bridge member34 by pressing thereupon with a convenient finger.

Referring now to FIGS. 8 and 9 in this embodiment of the aid a leafspring arrangement 37 is provided for exerting pressure upon themarginal edge region 11A of the main body 2 in addition to those arisingfrom the pressure exerted upon the elements 4 and 5 in the mannerconsidered above. The leaf spring arrangement includes a post 38upstanding from the main body. A spring member 39 is mounted cantileverfashion to the post and is secured thereto by a screw 40. The free endregion 41 of the spring member 39 is deformed to provide a sheetengaging part 42 which projects through a bore 43 provided in the mainbody 2. As will be noted the initial set or positioning of the springmember 39 is such that the part 42 protrudes slightly below the plane ofthe lower surface 16 of the main body.

The extent of the protrusion of the part 42 is such that the springmember 39 is able to exert a pressure on the marginal edge region 11Aduring the setting adjustments of the aid.

The step which is formed by the elements 12 and 13 can be continuedacross the full width of the underside of the drawing aid, as indicatedat the dashed line 44 in FIG. 9. The depth of the step 44 is less thanthe thickness of the sheet material to be used with the aid as the stepextension is intended to engage only with the upper regions of the sheetedge 11.

The aid is conveniently made from a transparent plastics material.

In a variation of the construction of FIGS. 8 and 9 the leaf springarrangement could be replaced or augmented by a press type of springassembly (not shown) which is depressible to exert pressure upon thesheet when it is required to prevent relative displacement between theaid and sheet and the sheet and surface.

I claim:
 1. A drawing aid for facilitating the drawing of lines or othermixtures upon a sheet of material having at least one sheet edge witheach such edge having a marginal sheet edge region associated therewithand lying upon a support surface, the sheet material being of suchthickness that the sheet is flexible or nonrigid, the aid comprising; anelongate blade-like portion; at least one guide edge for sheet markingmeans, the guide edge extending lengthwise of the elongate blade-likeportion for guiding the sheet marking means along a direction defined bythe guide edge; and resilient means so deformable relative to theelongate blade-like portion as to be engageable with a said sheet edgeof the sheet upon which the elongate blade-like portion is placed, suchthat said sheet edge provides a direction guide for positioning thedrawing aid during use with respect to the sheet.
 2. A drawing aid asclaimed in claim 1, and in which the resilient means comprises on eachside of the elongate blade-like portion means defining reference facesor edges, each face or edge adapted to engage with said sheet edge.
 3. Adrawing aid as claimed in claim 1, and in which the resilient meansincludes a pair of arms extending transversely of the elongateblade-like portion with each such arm defining a reference face forengagement with said sheet edge on deformation of the associated armtowards the support surface following engagement of the elongateblade-like portion with the sheet.
 4. A drawing aid as claimed in claim3, and in which each said arm is provided with an extension extendinglengthwise of the elongate blade-like portion, and located at suchposition relative to the associated arm as to overlie the marginal edgeregion associated with the edge that is engaged during engagement of thereference faces with the edge of the sheet.
 5. A drawing aid as claimedin claim 4, and in which each said extension defines surfaces forco-operation with the marginal edge region of the sheet associated withsaid sheet edge on deformation of the associated arm towards the supportsurface.
 6. A drawing aid as claimed in claim 1, and comprising meansfor indicating preferred positions for the user's fingertips on theresilient means when using the drawing aid.
 7. A drawing aid as claimedin claim 1, and in which said resilient means is able to exert pressureupon the marginal edge region of the sheet that is adjacent to said edgewhen the aid is cooperating with the sheet and is being urged intocooperation with the support surface.
 8. A drawing aid as claimed inclaim 7, and in which the resilient means includes a leaf springarrangement having a part adapted to co-operate with a said sheetmarginal edge region on engaging the aid with the sheet.
 9. A drawingaid as claimed in claim 1, and in which said resilient means is formedintegrally with the elongate blade-like portion.
 10. A drawing aid asclaimed in claim 1, and in which the elongate blade-like portion isformed separately from the resilient means whereby the guide edge can beselectively set with respect to the resilient means so as to enableselective variation of the direction of the guide edge relative to saidsheet edge.
 11. A drawing aid as claimed in claim 1, and in which theelongate blade-like portion is provided with stiffening means extendinglengthwise of the blade-like portion.
 12. A drawing aid as claimed inclaim 1, and in which the resilient means comprises a cantileverarrangement incorporating first means defining a reference face or edgeadapted for engagement with a said sheet edge and a second face adaptedto engage with the support surface when the drawing aid is rested uponsaid sheet lying on the support surface, said cantilever arrangementalso incorporating second means adapted automatically to engage with themarginal edge region of the sheet adjacent to said sheet edge after saidsecond face has been caused to engage with the support surface.